User's Manual

TSS 2. Generation BMW

Tire Safety System TSS 2nd. Generation, BMW

Dept. BEE

Dokument Nr.:

Document no.:

Änderungsstand:

Status of

modification:

Index:

3530.001.002.00.27

Bedienungsanleitung TSS BMW

User Manual TSS BMW

freigegeben am /date of release

8/31/05

2 Functional description

The wheel electronics are mounted within the tires and measure tire pressure, temperature and wheel electron-

ics. The measured data is sent from the wheel via a send stage in the wheel electronics. A system with relatively

seldom measured data transfer is adequate for tire pressure monitoring provided it features the additional option

of detecting sudden pressure loss. This enables the electronics in the wheel to be designed for minimum power

draw and battery operation.

All wheel electronics have their own code (ID) that is forwarded with the data at each transfer. The HF transfer

occurs in the 433 MHz range, referred to as the ISM range. The trigger functionality is achieved by a 125kHz LF

channel.

The control unit calls up the wheel electronics via the trigger transmitters every 54 s to send data messages.

Tire pressure and wheel electronics temperature are also measured every 3 seconds. When a pressure loss

> 0.2 bar on the last sent pressure value is detected, the wheel electronics switch immediately to fast-send

mode. In this situation, the wheel electronics measure and send every 0.8 seconds.

The TSS measures and transfers considerably more data than is necessary to ensure reliable basic function. It

can therefore use a data transfer path that is not assigned for the error-free transfer of each individual data pro-

tocol. Using the trigger function, an implausible and/or non-received data message can be requested again from

the corresponding wheel electronics.

The data sent by the wheel electronics is received via the digital antenna and is decoded. The decoded data is

transferred onwards to the control unit via a digital interface (LIN interface).

The control unit evaluates the received data and forwards the information to the driver information system as

required. This provides the driver with information on the necessary tire pressure or tire tension adjustments.

The main functional characteristics of the control unit are:

- A central warning algorithm and an algorithm for the wheel manager

- The vehicle-specific connection for the power supply system and manufacturer-specific operation and

display philosophy

The essential feature of wheel management is the self-learning system with automatic individual wheel detection

and the detection of the corresponding installed positions (wheel position detection).

Thanks to fast triggering of the wheel electronics when T 15 is ON, the system detects a flat tire well before the

start of a journey.